Simulation on the oblique penetration of an elliptical cross-section projectile into concrete

To obtain the ballistic characteristics of the oblique penetration of an elliptical cross-section projectile into concrete, a systematic study was carried out using numerical simulation. A reliable finite element numerical simulation model was constructed. The oblique angle, attack angle and axis spin angle that affect the ballistic deflection were decoupling. Numerical simulations of the oblique penetration of an elliptical cross-section projectile into concrete under different drop angles were carried out. The evolution laws of ballistic deflection and spin were deeply analyzed, and the mechanisms of ballistic deflection and spin were explained. The results show that the oblique angle and attack angle lead to the asymmetry of the force-bearing areas on the upper and lower surfaces of the projectile, and the attack angle also leads to the asymmetry of the surface stress of the projectile, eventually generating a deflection torque that prompts the deflection of the projectile. The angular velocity, attitude angle and ballistic offset of the projectile increase with the increases of the oblique angle and attack angle. In the case of oblique penetration with an oblique angle, the projectile in the upright position (γ=0°) deflects slowly and for a long time, while the projectile in the lying position (γ=90°) deflects quickly and for a short time. There is no absolute superiority or inferiority between the two positions in terms of ballistic stability. In the case of oblique penetration with an attack angle, the ballistic stability of the projectile in the upright position is better than that of the projectile in the lying position. The combined effects of the axis spin angle and oblique angle lead to the asymmetry of the projectile-target intersection. Besides offset and deflection, the projectile also has a self-rotating motion around the axis. When the axis spin angle increases from 0° to 90°, the projectile-target intersection condition undergoes a transformation from symmetry to asymmetry and then back to symmetry. The offset in the horizontal direction and the axis spin angle increment of the projectile first increase and then decrease. The research results provide important references for the practical engineering application of the elliptical cross-section projectile.